Process and device for splicing an optical cable to the conductor strand of an aerial line

ABSTRACT

The lashing device has at least one supply reel, which contains a lashing element which is to be applied in a continuous spiral. The supply reel is mounted on a journal so that it can revolve about its longitudinal axis, and the journal, together with the supply reel, is arranged so that, with simultaneous longitudinal movement along the conductor, this journal wraps around the conductor in a rotating manner.

BACKGROUND OF THE INVENTION

The device, which is known from DE 37 02 781 A1, for attaching anoptical cable to the overhead ground cable of a high-voltage linecomprises a stranding machine, which can be moved along the cable andcarries with it a cable drum, and a lapping machine, which is coupled tothe stranding machine and is equipped with a supply drum for a holdingtape. Both machines have a drive which moves the respective drum over anorbit about the overhead ground cable. Since the cable drum is guidedaround the overhead ground cable with a changing direction of rotation,the optical cable is wrapped around it in the manner of an SZ stranding.The holding tape, which is applied in a long lay, serves to fix thelapping formed by the optical cable.

The device, which is known from DE 32 28 227 C2, attaches an opticalcable with the aid of discrete lashing elements on a supportingconductor, but the retaining clamps, which serve as lashing elements,subject the cable to comparatively high mechanical loads. Moreover,there is a risk of the thermally expanded cable sagging between adjacentlashing elements, which may be disadvantageous in particular with regardto leakage currents occurring, but also with regard to the mechanicalloading.

SUMMARY OF THE INVENTION

An object of the invention is to provide a simple way of attaching anoptical cable to a conductor of an electrical overhead line in areliable and rapid manner. This object is achieved by means of a devicecomprising a supply drum for an optical cable being mounted to rotateabout a first axis; a supply reel for a first lashing element beingmounted to rotate around a first longitudinal axis; first means foraligning the optical cable parallel to a longitudinal axis of aconductor to form a unit as the optical cable is hauled-off the supplydrum; second means for displacing the supply drum and first supply reelin a direction of the first longitudinal axis of the conductor whilemaintaining the spaced orientation of the first axle; and third meansfor holding and rotating the first supply reel about a second axis whichis oriented parallel to the longitudinal axis of the cable so that afirst lashing element wraps around the unit in the form of a spiral.

The objects are also achieved by a method for attaching an optical cableto a conductor of an overhead line comprising the steps of providing alashing device having a supply drum for the optical cable mounted forrotation on a first axle; displacing the lashing device and supply drumalong the conductor of the overhead line; unwinding the cable from thesupply drum while maintaining the orientation of the first axle andplacing the cable adjacent the conductor to extend parallel thereto toform a unit; and wrapping a first lashing element around the unit in aspiral path by rotating a supply reel around a first axis as the elementis withdrawn therefrom and rotating the reel around a second axisparallel to the longitudinal axis of the unit.

The supply reel, which is mounted so that it can revolve about itslongitudinal axis, allows the haul-off rate to be increased and thusallows the cable installation time to be reduced. Moreover, the helicalmovement of the supply reel around the conductor allows the lashingelement to be braided around the optical cable in a continuous coil orspiral.

Since the comparatively heavy cable drum does not have to move aroundthe overhead ground cable, the mechanical structure of the device isconsiderably simplified. In addition, there is no need for anycentripetal forces caused by the revolution of the cable drum to becompensated for by means of a corotating counterweight or to be pickedup and taken off by bearings of correspondingly large dimensions. Thisallows the device to be of a more lightweight structure and to be movedover the conductor much more quickly than has hitherto been customary,so that the assembly time and assembly costs can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of an exemplary embodiment of a lashing device inaccordance with the invention,

FIG. 2 is a partial end view of the lashing device in accordance withFIG. 1 as seen in the longitudinal direction of the conductor,

FIG. 3 is an enlarged view of the mounting of a supply reel on ajournal, and

FIG. 4 is a diagrammatic view of a modification of the lashing methodaccording to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a lashing device AV for attaching an optical cable OC to astranded conductor ES of a high-voltage overhead line. The strandedconductor may be an overhead ground cable or a phase cable. The opticalcable OC is arranged on a supply drum VT, which is mounted for rotationin a U-shaped bracket BG, which has bracket arms BG1 and BG2 (see FIG.2). In detail, the supply drum VT is suspended, by means of a rotatableaxle DT, in hooks HK1 and HK2, which are arranged at the end of the twobracket arms BG1 and BG2.

Expediently, the rotatable axle DT is mounted with respect to thebracket arms BG1 and BG2 by means of ball bearings KL1 and KL2, in orderto keep the haul-off forces as low as possible. In order to suspend therotatable axle DT in place, retention eyelets OS1 and OS2 are arrangedat each of its outer ends. In order to prevent the cable drum VT fromfalling out, a lock is arranged at each of the openings of the hooks seelock VE1 (FIG. 1) HK1.

In order to prevent the optical cable OC from being unwound too quicklyas a result of the supply drum VT continuing to revolve in the event ofthe lashing device AV being at a standstill or decelerating, suitablebrake devices are to be provided. As can be seen also from FIG. 2, thesedevices may act on the outside of the supply drum VT (braking elementsBT1 and BT2). In addition, or independently of this, it is also possibleto provide a further braking device for the optical cable OC itself.This braking device acts directly on the respective cable and preventsan excessively large loop from being formed. In FIG. 1, two of thesebraking devices which act on the cable are present and are denoted byBC1 and BC2. They are advantageously designed as brush brakes and arearranged offset by 180°.

A guide device LE (e.g. designed as a guide plate) is provided forguiding and feeding the optical cable to the particular conductor ES,which guide device narrows in the direction of passage, is curved in thedirection of passage of the cable OC and forms a trough-like agroove-like depression in which the cable OC is reliably guided. Thisguide device LE has a rim LR1 and LR2 (FIG. 2) which is drawn uplaterally, which rim prevents the optical cable OC from springing out ofthe curved guide path. The guide device LE is advantageously held on apin AE in such a way that it can be swung down, so that it can be swungdown into a position LE* (cf. FIG. 1), if, for example, the lashingdevice is to be moved or guided around a pylon.

By means of the guide device LE, the optical cable OC is brought closerto the associated conductor ES or is pressed onto the latter, theoptical cable OC and the conductor ES both running through the lashingdevice AV (FIG. 2) together. To this end, the lashing device AV has atubular sleeve RH, which has a longitudinal slot RS (only part of whichcan be seen here), which runs in the direction of the axis of theconductor ES, i.e. running from left to right in the drawing. By meansof this continuous longitudinal slot, the lashing device AV can beattached to the conductor ES from the side. The slot RS lies below theoptical cable OC and hence also below the conductor ES, thus forming aprotection against these elements springing out. The slotted sleeve RHis fixedly connected to the main supporting element HT, serving as acrossarm, which element provides the connection to the holding bracketBG for the cable supply drum VT. Thus the lashing device AV comprises,in a fixedly integrated manner, the cable drum VT and the actual lashingpart with the tubular sleeve RH, the two parts being fixedly connectedto one another via the crossarm HT.

The lashing device AV is guided on the conductor ES by means of at leasttwo wheels, and one of these wheels, in the present case the front wheelAR, is designed as a driving wheel. This wheel AR is used to generatethe requisite driving force for applying the lashing elements. Thiswheel AR is therefore in frictional engagement with the surface of theconductor ES, in which case the wheel may expediently be provided with acoating which increases the friction, for example of rubber or the like.The further or additional wheel or wheels (in this case only a singleexit-side wheel FR is shown) are used to support the lashing device AVon the conductor ES. All the wheels used have on their circumference agroove profile, the size of which is matched to the diameters of theconductor ES.

A first bevel gear SR1 is connected to the driving wheel AR, which bevelgear transmits the revolving movement of this wheel to a second, smallerbevel gear KR1. This bevel gear KR1 is connected, preferably by means ofa universal joint, to a shaft WL which runs inside the tubular sleeve RHand is connected at its other end, preferably also by means of auniversal joint, to a flange which has a bevel gear SR2 on the outside.

In the following text, it is for the time being assumed that only onelashing element AE1 is to be used for lashing the optical cable AC tothe conductor ES. For this purpose, a supply reel VS1, which isindicated in dashed lines, is provided, which supply reel is arranged insuch a manner that it can revolve about its longitudinal axis LA1, as isexplained in more detail with reference to FIG. 3. Moreover, it isintended that this supply reel VS1 should rotate about an axis LA3 whichlies symmetrically, i.e. approximately in the center, between theconductor ES and the optical cable OC. For this purpose, a revolvingsleeve DH1, which serves as a support for the supply reel VS1, ismounted for rotation on the slotted tubular sleeve RH. Thus, by rotatingthe revolving sleeve DH1, the supply reel VS1 can be made to rotateabout the axis LA3, because the flange which has the bevel gear SR2 isfixedly connected to the revolving sleeve DH1. Thus, the force istransmitted via one or more transmission elements which are preferable,bevel gears. The outline of the rotational movement of the supply reelVS1 in the event of rotation of the revolving sleeve DH1 is alsoillustrated in dashed lines. The revolving sleeve DH1 has a grip HG1, bymeans of which it can be attached to the outside of the slotted tubularsleeve RH after the latter has been attached to the conductor ES. Therevolving sleeve also has a longitudinal slot which is not shown hereand which extends in the direction of axis LA3.

Owing to the revolution about the axis LA1, the lashing element AE1 ispulled off the supply reel VS1 and passes outward over correspondingguide devices, e.g. a flyer FL which also rotates with the reel VS1 and,from here, runs at an angle onto the combination of conductor ES andoptical cable OC so that the lashing element AE1 is wound continuouslyonto this combination.

In many cases, it is desirable to apply two lashing elements AE1 andAE2, in which case the application preferably takes place with reversedlays (in the form of a crossed spiral). For this purpose, in the presentexample a bevel gear SR3 is provided, in which a pair of bevel gears KR2and KR3, which can revolve only about their longitudinal axis but areotherwise fixed, engages. By means of these bevel gears KR2 and KR3, therevolving movement provided by the driving wheel AR is transmitted tothe bevel gear SR3, which is flanged onto a revolving sleeve DH2, thisrevolving sleeve likewise being able to rotate about the slotted tubularsleeve RH. Analogously to the supply reel VS1, a supply reel VS2 whichcan revolve about its longitudinal axis is provided on the revolvingsleeve DH2, sleeve with the supply reel VS2 rotates in the oppositedirection of the arrow PF2 to the direction of arrow PF1 for therevolving sleeve DH1 manner to apply a crosslay with the two lashingelements AE1 and AE2.

Advantageously, the axes of rotation LA1 and LA2 of the supply reels VS1and VS2 include an acute angle with the longitudinal axis LA3 of thecable-conductor combination, and specifically they are inclined towardthe haul-off direction, i.e. to the left in the present example. Theangular deviation from 90° preferably approximately corresponds to thewrap-around angle of the lashing elements on the conductor ES, i.e. itadvantageously lies between approximately 10° and 20°, preferably around15°. As a result, the haul-off operation itself can be facilitated. Iftwo supply reels VS1 and VS2 which rotate in opposite directions areprovided, in most cases it is possible to do without correspondingbalancing weights if it is ensured that the two supply reels are in eachcase positioned offset through 180°. If only one supply reel VS1 isused, it is expedient to allow a corresponding counterweight to rotatewith it in order to balance out the forces.

FIG. 3 shows part of the annular outer delimitation of the revolvingsleeve DH1, in section. A journal or shaft ZA1 is fixedly attached tosaid sleeve, to which journal, in turn, the supply reel VS1 with thelashing element AE1 (which in this figure is shown only in the form of ablock) is attached by means of a quick-acting closure element SVE, thusforming a center sleeve. The quick-acting closure SVE is selected insuch a way that the supply reel can rotate with respect to the fixedjournal ZA1, i.e. it expediently contains a ball bearing or rollerbearing. The supply reel VS1 is placed on a bottom part UT1 and heldfixedly thereon, which bottom part is mounted, by means of ball bearingsor the like (not shown in more detail here), in such a manner that itcan revolve with respect to the journal ZA1. A hysteresis disk ormagnetic disk MB2 is attached to the bottom part UT1, which diskrotates, together with the supply reel VS1, about the axis LA1. Apermanent magnet MB1, preferably a ring magnet, is arranged in theregion of the revolving sleeve DH1, separated from the disk MB2 by agap, the rotating movement of the supply reel or the magnetic disk MB2with respect to the magnet MB1 generating a braking force which preventsthe lashing element AE1 from running off too quickly and hence formingundesirable loops. Naturally, as an alternative to the magnetic brakesit is also possible to use all other known braking devices, such as forexample brush brakes, drum brakes or the like, in order to haul thelashing element AE1 off the supply reel VS1 under tensile stress andthus to exert a corresponding tensile stress on the conductor-cablecombination ES/OC.

Advantageously, tape-like structures are used as the lashing elements,e.g. AE1, with the result that the thickness and pressure can be keptrelatively low even under high and fixed tensile stresses on the lashingelement at the optical cable OC. Preferably, self-adhesive lashingelements are used, because these hold the conductor-cable combinationES/OC particularly successfully and securely. These lashing elements mayalso, in addition, be provided with a reinforcement fabric or anadditional reinforcement layer in the form of filaments or rovings andthe like, which correspondingly increases their tensile force and theirrobustness.

The longitudinal movement of the lashing device AV can be ensured bymeans of a drive unit AM which is structurally connected thereto andcontains, for example, an internal combustion engine or a motor which ispowered electrically via suitable power supply lines. This drive unit AMruns along the conductor ES by means of running wheels RM1 and RM2 and acorresponding counterpressure wheel RM3 and is connected in anarticulated manner to the actual lashing device AV by way of a couplingKP. As an alternative to a coupling KP, it is also possible to use arope or rod or the like.

It is also possible to drive the lashing device AV by means of adrawing-in wire which is wound, for example, onto a drum which isattached to a pylon or to the ground, as a result of which the lashingdevice AV moves along the conductor ES.

In a modification of the invention or also independently thereof, it ispossible to proceed in such a way that the fiber-optic cable which is tobe installed is continuously attached along a conductor of thehigh-voltage overhead line in an arrangement which is combined to form acable train, using a continuous attachment means in the form of a woundstrip. The cable train comprises a traveling trolley, a cable trailerand a lashing machine, which are fixedly coupled to one another and forma single unit. The cable train as a whole is pulled along a suspensionspan by the traveling trolley, the fiber-optic cable which is situatedin a cable drum in the cable trailer being unwound and, with the aid ofthe lashing machine of the cable train, being attached preferably to theoverhead ground cable of the high-voltage overhead line. In this case,attachment takes place using a continuous wound tape which is woundaround the conductor and the fiber-optic cable in the form of a spiral.This wound tape comprises, by way of example, a glass or plastic tapewhich is wound in a simple, continuous manner. However, depending on thedesign of the lashing machine, it is also possible to coil two tapes ina crosslay around the conductor and the fiber-optic cable, if a higherlevel of reliability is required. The fiber-optic cable which is to beinstalled can be lashed either to the overhead ground cable or to aphase cable of the high-voltage overhead line.

The cable train can be moved along within a suspension span using adrive unit in the traveling trolley, in which case a remote control isadvantageously used for this purpose. However, the cable train can alsobe moved along with the aid of a dielectric drawing-in wire which isattached to the traveling trolley and at the end of the suspension spanis guided over diverting rollers to a wire winch.

The fiber-optic cable which is to be installed and is wound on the cabledrum of the cable trailer is generally very lightweight (approx. 20 g/m)and runs off the cable drum under slight braking, which drum isinstalled in a frame provided with running rollers, in the form of thecable trailer. The three functional components of the traveling trolley,cable trailer and lashing machine are coupled to one another and arethus guided jointly along a suspension span.

In the event of faults occurring, such as for example in the event offailure of the remote control, it is provided, in the event of such afault, for the cable train to be coupled to an additional travelingtrolley from the end of the suspension span and to be pulled to the endof the suspension span. This ensures that faults in the drive system ofthe cable train can be overcome in a relatively simple manner.

The above-described embodiment of a cable train is explained in moredetail with reference to FIG. 4. This figure shows a suspension span SFbetween two pylons M of a high-voltage overhead line, with the phasecables or voltage cables SS and an overhead ground cable ES. In thiscase, a fiber-optic cable is being installed on the overhead groundcable ES of the high-voltage overhead line, using a cable train KZ. Thiscable train KZ comprises individual functional components which arefixedly coupled to one another, namely a traveling trolley LK, a cabletrailer KW with a cable drum KT, and a lashing machine LM. Using thelashing machine LM, a wound tape (lashing tape) WB is wound around thefiber-optic cable OC4, which is being installed on the conductor ES andthe overhead ground conductor ES in the form of a spiral, this figure,by way of example, showing the winding in a crosslay with two woundtapes. In more simple cases, winding can also take place with only onewound tape. The cable trailer KW comprises a cable drum KT, on which thefiber-optic cable OC4 to be installed is wound. At the head of the cabletrain KZ there is situated the traveling trolley LK, which is pulledalong the suspension span SF either with the aid of a dielectricdrawing-in wire ZS or by means of its own drive unit. In the case wherea drawing-in wire ZS is used, the latter is coupled to the travelingtrolley from the end of the suspension span and is guided downward to anadditional wire winch ZW via diverting rollers UR on the pylon M. If adedicated drive unit is used, it is expedient for it to be controlledwith the aid of a remote control device, so that there is no need toinstall additional lines or cables.

What is claimed is:
 1. A device for attaching an optical cable to aconductor of an electrical overhead line using a first lashing element,said device comprising a supply drum for the optical cable being mountedto rotate about a first axle of the device; a supply reel for the firstlashing element being mounted to rotate about a first longitudinal axis;first means for aligning the optical cable as it is hauled-off of thesupply drum parallel to the longitudinal axis of the conductor; secondmeans for displacing the device with the supply drum and the firstsupply reel in a direction of the longitudinal axis of the conductorwhile maintaining the spatial orientation of the first axle; and thirdmeans for holding and rotating the supply reel about a second axis whichis oriented parallel to a longitudinal axis of the cable so that thefirst supply reel moves about the longitudinal axis of the cable to wrapthe first lashing element around a unit comprising the conductor and theoptical cable to form a continuous spiral.
 2. A device according toclaim 1, which includes a guide device which deflects the first lashingelement toward a unit formed by the conductor and optical cable, saidguide device being mounted to rotate with the first supply reel aboutthe second axis.
 3. A device according to claim 1, which includes asecond supply reel carrying a second lashing element, said second supplyreel being mounted to rotate around a second longitudinal axis andfourth means for rotating the second supply reel about the second axis.4. A device according to claim 3, wherein the fourth means rotates thesecond supply reel about the second axis in a direction opposite to therotation of the first supply reel.
 5. A device according to claim 3,wherein the third means has a tubular sleeve which is slotted in thedirection of the longitudinal axis of the conductor, a first revolvingsleeve which supports the first supply reel being mounted on the tubularsleeve so that it can revolve about the second axis, and the fourthmeans has a second revolving sleeve which supports the second supplyreel being mounted on the tubular sleeve so that it can revolve aboutthe second axis.
 6. A device according to claim 5, wherein the first andsecond revolving sleeves are each provided with a bevel gear, whichbevel gears are interconnected by a transmission element.
 7. A deviceaccording to claim 6, which includes a drive wheel which is supported onthe conductor and is connected to an additional bevel gear, a shafttransmitting the revolutions of the driving wheel and additional bevelgear to the bevel gear assigned to the first revolving sleeve.
 8. Adevice according to claim 5, which includes a permanent magnet and,opposed to the permanent magnet at a distance therefrom, a magnetic discbeing provided in one of the revolving sleeves, the magnetic discrotating together with the corresponding supply reel, which is arrangedon a shaft about the longitudinal axis of the supply reel.
 9. A deviceaccording to claim 1, wherein the longitudinal axis of the conductor andthe first longitudinal axis of the first supply reel include an anglewhich lies in a range between 70° and 80° and facilitates hauling-off ofthe first lashing element.
 10. A device according to claim 1, whereinthe first means has a guide device which narrows in the direction ofpassage of the optical cable to provide a trough-like depression andguides the optical cable toward the longitudinal axis of the conductorso that it approaches the conductor.
 11. A device according to claim 1,which includes at least one braking device which acts on one of theoptical cable, a supply reel and the supply drum.
 12. A device accordingto claim 11, which includes a draw-in wire which moves the device alongthe conductor and is connected to a wire winch.
 13. A device accordingto claim 1, wherein the device includes a holder with two bracket armsfor suspending the first axle with the supply drum beneath theconductor.
 14. A device according to claim 1, which includes a driveunit which is supported on the conductor and is connected to the device.15. A device according to claim 14, wherein the drive unit is arrangedas a traveling trolley which is coupled to the device.
 16. A deviceaccording to claim 15, wherein the supply drum is arranged in a cabletrailer which is provided with running rollers and the cable trailer iscoupled to the device and to the traveling trolley.
 17. A deviceaccording to claim 1, wherein the lashing element is a tape.
 18. Amethod for attaching an optical cable to a conductor of an electricaloverhead line, said method comprising providing a lashing device havinga supply drum for an optical cable mounted for rotation on a first axle;displacing the lashing device and supply drum along the conductor of theelectrical overhead line; unwinding the cable from the supply drum whilemaintaining an orientation of the first axle and placing the cableadjacent the conductor to extend parallel thereto to form a unit andwrapping a first lashing element around the unit in a spiral path byrotating a supply reel around a first axis as the element is withdrawntherefrom and rotating the reel around a second axis extending parallelto the longitudinal axis of the unit.
 19. A method according to claim18, which includes wrapping a second lashing element around the unit ina spiral path by rotating a second supply reel about a secondlongitudinal axis and, as the element is withdrawn therefrom, rotatingthe second supply reel around a second axis in an opposite direction tothe rotation of the first supply reel so that the spiral path of thesecond lashing element is opposite to the spiral path of the firstlashing element.
 20. A method according to claim 18, wherein saidproviding the lashing device provides a cable trailer which holds thesupply drum which are suspended on the conductor and coupled to atraveling trolley which is likewise suspended on the conductor todisplace the lashing device and supply drum along the conductor.
 21. Amethod according to claim 20, which includes pulling the travelingtrolley across a suspension span using a dielectric draw-in wire whichis attached to the traveling trolley and a wire winch.